Hi yall,
So I bought my G20sf this past november and I was having some trouble with it when it came to the full power loads (i.e. Underwood, DT, Buffalo etc) I would get FTF and sometimes the gun would not even begin to cycle or leave battery after firing it.

I had a G20 that worked fine with light and heavy loads. If the gun would not cycle or leave battery I would suspect something went wrong most likely during assembly. Not leaving battery with full power loads doesn't sound right at all.